Gas entrained removable mandrel

Abstract

This invention involves the incorporation of gas in the matrix of a mandrel. The incorporation of gas, as foam, into the matrix of a mandrel reduces the density of the mandrel. The resulting mandrel is easier to remove from finished product by washout or disintegration. Therefore it is of great value in the use of mandrels in making hollow composite parts.

What is claimed: 
     
         1 . A mandrel for utilization in the fabrication of a plastic/composite which is formed with entrained air or gas. 
     
     
         2 . The mandrel of  claim 1  containing 5% or more of its volume as air or gas, as foam. 
     
     
         3 . The mandrel of  claim 1  produced by pneumatic means. 
     
     
         4 . The mandrel of  claim 1  produced by mixing foam into the mandrel matrix before hardening the matrix. 
     
     
         5 . The mandrel of  claim 1  produced by chemical means to entrain the gas in the matrix. 
     
     
         6 . A mandrel that is formed utilizing entrained gas, a hardening matrix, and a binder. 
     
     
         7 . The mandrel in  claim 6  which contains a controlled amount of entrained gas greater than 5%. 
     
     
         8 . The mandrel in  claim 6  which contains a liquid matrix that is able to harden to a desired shape upon setting or curing or drying. 
     
     
         9 . The mandrel in  claim 6  which contains a binder that is able to impart special properties to the mandrel matrix including strength, dispersibility, thermal properties and/or color. 
     
     
         10 . A mandrel formed with a dense outer shell and filled with foamed matrix material.